The present invention relates to a case for a remote control key that communicates with a drive controller, which locks and unlocks a lock device, to remotely control the lock device.
In recent years, lock devices for use in doors of vehicles and houses are locked and unlocked through remote control. For example, a remote control system has been proposed for locking and unlocking a lock device when a portable device is operated, which is provided with a communication function. A portable device used in a conventional remote lock system outputs a wireless signal including an 10 code when operated by a user. A drive controller, which electrically drives the lock device, receives the wireless signal from the portable device and executes a command (lock command or unlock command) in accordance with an ID code included in the wireless signal. For example, with a portable device for a keyless entry system, the user approaches a vehicle and pushes an unlock button of the portable device near the vehicle to unlock the door of the vehicle.
Japanese Laid-Open Patent Publication Nos. 2003-113683 and 2002-322841 describe portable devices used in smart entry systems. In a smart entry system, a user holding the portable device approaches a vehicle to unlock the vehicle door and moves away from the vehicle to lock the vehicle door. A mechanical key is retainable in the portable device.
The portable device of the prior art includes a case body, which is formed by a first case shell and a second case shell, and a circuit board, which is accommodated in the case body. Communication circuits and control circuits are formed on the circuit board. The first and second case shells have a snap-fit structure so that they can be snapped together. A rubber packing is arranged between the two case shells so that the portable device has high water resistance. When a case is formed by fastening first and second case shells to each other through a snap-fit structure, creep deformation may occur in the snap-fit structure due to the effects of wear and temperature. This reduces the fastening force of the two case shells. The reduction in the fastening force may lower the water resistance of the two case shells or cause the two case shells to fall apart.